4 day Spring sale at Jaycar has this battery down from $899 to $399. Cannot comment on how good it is, but generally Jaycar is better than eBay IMO.
Their info: This 100Ah model can provide continuous current up to 50A, with peaks of up to 100A. It’s not suitable for a primary vehicle starting battery, however is absolutely perfect for house batteries, backup batteries, and virtually any other application where you would typically use a large lead acid / AGM battery.
Battery Peak Current
100A
Internal Resistance
60mΩ
Battery Chemical Composition
Lithium Ferrous Phosphate (LiFePO4)
Battery usage
Bulk Storage
Peak Discharge Duration
5sec
Amp Hour Rating
100Ah
Continuous Current
50A
Type of battery
li-ion
20 Hour Capacity
100Ah
Connection Type
M8 Bolt/Nut
Nominal Voltage
12.8V
Cut-Off Voltage
9.2V
RRP seems ludicrous